Volumetric Efficiency and Dyno's

[Fiat48]

Dyno numbers Vs Volumetric efficiency
Since an internal combustion engine is nothing more than an air pump, VE is what power is all about.
Since there seems to be so much controversy about Dyno claims I submit the following:
After much research of what today's capable VE's are, the best stated facts I found are below. I found this at this website:http://www.epi-eng.com/ET-VolEff.htm
"In a four-stroke naturally aspirated engine, the theoretical maximum amount of air that each cylinder can ingest during the intake cycle is equal to the swept volume (displacement) of that cylinder (0.7854 x bore x bore x stroke). Since each cylinder has one intake stroke every two revolutions of the crankshaft, then the theoretical maximum volume of air it can ingest during each rotation of the crankshaft is equal to one-half its displacement. The actual amount of air the engine ingests compared to that theoretical maximum is called volumetric efficiency (VE). There are many factors which determine how much torque an engine can produce, but the fundamental determinant is the mass of air it can ingest into the cylinders.
For contemporary naturally-aspirated, gasoline-fueled, two-valve-per-cylinder, pushrod engine technology, a VE over 95% is excellent; 100% is achievable, but quite difficult. The best of the best have achieved 110% by means of extremely specialized development of the complex system comprised of the intake passages, cylinder heads, valve train, and exhaust passages."
I decided to prove this theory of 110% as a best achieved VE and compare it to my camshaft design software "Controlled Induction." I did this to try to compare the software's accuracy in predicting "maximum possible horsepower" with regard to VE. This program assumes perfect tuning in a perfect environment. "Controlled Induction" also assumes you have enough cylinder head available to do this job. That is "Intake port area required" which is a measurement of "choke area" or most restrictive part of the intake port. Note how this requirement changes for each engine.
To get an idea of that choke restriction, a set of Dart 360 Aluminum cylinder heads professionally ported that I ran in 1988 in PGF measured 4.051 and the Intake flowed 340 cfm at . 570 lift and the exhaust flowed 240 cfm at .570 lift @ 28". Keep that in mind as you see intake port area requirements for the engines below.
To keep things simple, Controlled Induction barometer was set at 29.92, which would be perfect conditions of 0 elevation, 0 humidity and 60 degrees temperature.
I wanted to compare the "claimed HP" of known respected engine builders who sell engines. The ones I chose were what I could find on the web.
Steve Schmidt
Reher-Morrsion
Sonny Leonard
1st to compare is Steve Schmidt's 565 inch "Terminator" claimed at 1150 HP. and 864.6 lbs of torque
Engine specs:
Bore: 4.600
stroke: 4.250
compression ratio is not listed, so we'll have to assume 15 to 1.
Dyno readings of 1143.8 HP at 7700 rpm
Now to match that with controlled induction:
Controlled induction says that at 100% VE that the engine can make 1149.792 HP at 7700 rpm and can make 864.043 Ft lbs of torque using a max torque efficiency of 104.6%
Controlled Induction says this is possible and given today's technology, 100% VE and 104.6% torque efficiency is possible.
The numbers are believable in my opinion. But Intake port area required is 5.016.
Next engine is Sonny Leonard's 565 claimed at 1075 HP @ 7600 rpm and 832 ft lbs torque.
Controlled induction says this is possible with 94.75% VE and 100.75% torque efficiency.
Again, I have no compression ratio and assume 15 to 1.
Intake port area required is still 5.016
If the engine had 14.1 compression, then 101.5% VE and 108% torque efficiency would be required.
But the Intake port area required jumps to 5.374.
Again, the numbers are believable.
Next is Reher-Morrison's super series 565 making a claimed 1035 HP and 815 lb of torque.
This time we are given a compression ratio and it is 14.1.
But the actual dyno chart shows 1020 HP @ 7200 rpm and peak torque of 820 ft lbs.
By now we know that either reading can be matched with controlled induction. We'll use the 1035hp and 820 torque to give them the benefit of the doubt.
Controlled Induction says that is possible with 103.20 VE and 106.40 torque efficiency.
Now the Intake port area required is still 5.374
Believable.
Steve Schmidt = 100% VE and 104.6 Torque efficiency (assumes 15.1 compression ratio)
Sonny Leonard= 94.75% VE and 108% torque efficiency (assumes 15.1 compression ratio)
Reher Morrsion= 103.20% VE and 106.40 torque efficiency (known 14.1 compression ratio)
This leads me to believe the statement is accurate:
Next I tried to match a Pro Stock engine. Best information I could find was 1300 HP at 8750 rpm with peak torque of 824 ft lbs. Since the "kings of unblown" don't give out much information, some things are assumed.
Bore 4.600
Stroke 3.76
Compression 15.5 to 1
Controlled induction was able to match this with a VE of 108.85% and torque efficiency of 109.18%
And the intake port area required is a whopping 5.511
Remember that the preceding was at 29.92 barometer, 60 degrees F and 0% humidity, a far cry from real actual conditions and real world operating conditions are less and therefore less power is made, regardless of engine corrections to tuning.
By now, you may have guessed why I don't participate when I hear claims of high horsepower when the I have to put in VE numbers of 130% and sometimes more to match the power claimed. When I see those, it's "Hot Dyno" time as far as I am concerned.
However, one particular claim of a 490.4 cubic inch Chevy that made 812 HP and 700 foot lbs of torque at 6300 rpms I was able to confirm that is possible. I never saw any real specs on the motor, but using some assumption I was able to come up with the following:
with a 15.1 compression ratio
at 100% VE the engine could make 817.465 HP and at 100% torque efficiency 717.801 ft lbs torque. And since the rpm is way low only 3.580 Intake port area is required.
with a 14.1 compression ratio
at 106.5% VE the engine could make 812 HP and at 104.50% torque efficiency 700 ft lbs of torque. Intake port area required increases to 3.813.
with a 13.1 compression ratio
at 114.7% VE the engine would make 812 HP and at 112.60% torque efficiency 700 ft lbs. Intake port area required climbs further to 4.107.
At 13 to 1 or less compression, I'd have to say that based on what I have learned, it's not reasonable to believe the HP numbers.
That doesn't say that I agree the engine makes that much power. I am saying that if it has at least 13.5 to 1 or more compression, I can see how it is possible.
If anyone would like me to run their motor through "Controlled Induction" and show you POSSIBLE maximum HP, then I will be glad to do so. Blown motors also. I had planned to do screen shots of each configuration but this post turned out ot be a bit long. But I will do so if anybody wants it.

[UBFJ #454]

Is this why you asked me for "Ms. Monneypenny's" Bore, Stroke and CR? If so, what VE for the Hp did you come up with for her?

[Fiat48]

Originally posted by BEAR_454PE
Is this why you asked me for "Ms. Monneypenny's" Bore, Stroke and CR?
Yes, partly. I like to also watch the compression ratio trends along with bore and stroke. I have been trying to match known dyno numbers with my camshaft program for a long time. I'm also trying to get an idea of how much power it takes to push a particular type race boat (Jet, Hydro, flat) X amount of MPH. Kinda like the data base we have had on cars for years. But obvious the boats have a lot more variables. And any "old days" data not much good since the course has changed in drag boats which changed MPH and ET. Thanks for the specs and good luck with your boat!
I just saw you edit your post and want me to run it through. I'll post it here and edit shortly. Takes a bit.

[UBFJ #454]

Fiat - I was editing my post while you were posting your answer ... Would you read my addition and answer?

[Fiat48]

Originally posted by BEAR_454PE
Fiat - I was editing my post while you were posting your answer ... Would you read my addition and answer?
Bore: 4.600
stroke 4.250
C/r 15.05
To match 1275 Hp @ 6490 rpm You would have to have a VE of 120.20% and an Intake port area of 5.102
110@VE would be 1069.575 HP @ 6490 and the intake port area drops to 4.669
105% VE would be 1020.958 HP @6490 and the intake port area drops to 4.457
100% VE would be 972.341 HP @6490 and the required intake drops again to 4.244
I couldn't do torque since I couldn't find it on your website.

[UBFJ #454]

Fiat -
Ms. Moneypenny's actual Pk #'s are: 1288 @ 7,300 (C-16 Only) & 945.3 @ 5,600 (Again, C-16 Only) ... What values do you come up for these #'s? Thanks in Advance.
Jak

[CARLSON-JET]

Nice ... Fiat, is your cam program accesable to me.. average joe...I would also like to see just a few #'s for some way lower powered around 4-600 h.p typical 4.25 bore 4" stoke with 9 to maybe up to 11-1 comp ratios.... again .. nice work . R.B.

[LakesOnly]

Question: In all the above examples of motors you have evaluated, your final conclusion/conceivability on their claimed HP(s) was based on the minimum intake port cross-section ("choke area"). That is to say, it seems you determined whether the HP figures were realistic based on whether engine utilized heads that could indeed flow on par with the demands of the engine, based on your program.
If this is true, then it looks to me like your program could not only be used to evaluate optimum intake port cross-section for a specific engine, but perhaps the equation could be reconfigured to put any unknown "x" variable on the other side of the equation (instead of choke area), and plug all the known numbers into their respective points in the program and thereby find the best fit for the missing link to the equation. (Example: with this intake port cross-section and that bore and stroke and volumetric efficiency of 105%, 750Hp is possible with "x" compression ratio.) And your program could also determine c/r required? Is this the case?
LO

[Fiat48]

Originally posted by BEAR_454PE
Fiat -
Ms. Moneypenny's actual Pk #'s are: 1288 @ 7,300 (C-16 Only) & 945.3 @ 5,600 (Again, C-16 Only) ... What values do you come up for these #'s? Thanks in Advance.
Jak
117.8% VE to make 1288 @ 7300 and 114.10% Max Torque Efficiency with an intake port area of 5.156 required.

[Fiat48]

Originally posted by LakesOnly
Fiat, I just re-read...
Question: In all the above examples of motors you have evaluated, your final conclusion/conceivability on their claimed HP(s) was based on the minimum intake port cross-section ("choke area"). That is to say, it seems you determined whether the HP figures were realistic based on whether engine utilized heads that could indeed flow on par with the demands of the engine, based on your program.
If this is true, then it looks to me like your program could not only be used to evaluate optimum intake port cross-section for a specific engine, but perhaps the equation could be reconfigured to put any unknown "x" variable on the other side of the equation (instead of choke area), and plug all the known numbers into their respective points in the program and thereby find the best fit for the missing link to the equation. (Example: with this intake port cross-section and that bore and stroke and volumetric efficiency of 105%, 750Hp is possible with "x" compression ratio.) And your program could also determine c/r required? Is this the case?
LO
Yes it will do that. What I was doing was just letting it call out the min required port area and ASSUME the engine builder has that available. And why I gave some figures on a head I measured once, though a long time ago. Yes, reread..lot of meat here. Took a few days.

[UBFJ #454]

Thank You ... Our #'s & Yours Differ by Less Than 1/2 of a Percentage Point. At some time I'd like to get together and chat a bit.
Note that the "Penny's" Intake Port Area is Somewhat Larger than 5.156. The Heads are 12 degree, ProFilers that have been "Worked" Extensivelyand Flow Accordingly.
P.S.: It's nice to see someone else who's willing to post Technical Material and Share Info.

[Fiat48]

Originally posted by CARLSON-JET
Nice ... Fiat, is your cam program accesable to me.. average joe...I would also like to see just a few #'s for some way lower powered around 4-600 h.p typical 4.25 bore 4" stoke with 9 to maybe up to 11-1 comp ratios.... again .. nice work . R.B.
O.k I will try. Just remember these are Maximum Possible for the cubic and compression ratio. And you have to have the cylidner head to make it happen.
Typical 454
Bore 4.250
stroke 4.00
C/R 9 to1
To simplify and since we aren't trying to match any particular motor, we'll just shoot for 100% VE and 100% Torque efficiency.
468 hp @ 6500 and 398.18 torque (requires 3.415 port area)
raise compression 9.5 to 1
493 hp @ 6500 and 420.310 torque (port area stays same
raise compression 10 to 1
519.857 @ 6500 and 442.431 torque (same port area)
raise compression to 11.1
571.843 @ 6500 and 486.675 torque (same port area)
_______________________________
Back to 9 to 1 but RPM to 7000
503.8 HP at 7000 and 398.18 torque (port area increases to 3.678)
raise comp to 9.5 to 1
531.8 HP at 7000 and 420.310 torque (same port area required.
raise compression 11 to 1
615.8 hp at 7000 and 486.675 torque (same area)
You didn't say rpm so I assumed.

[bigkatboat]

I've found in unblown motors, often the 'choke' area is the "port to seat to face area. Velocities and 'wetted areas' have the greatest effect on mass flow. If any of the afore mentioned areas have a sharp angle, incorrect radius, or incorrect (abrupt) angle change, the mass flow may be severely disrupted. The 100% + figures shown above are a direct result of (the builder's) personal port/ head design. Their attempts to "put 10 lbs in a 5 lbs bag", seem to be working. In working with lower RPM (I/O motors) configurations, we have found a constant, that is a % # of port diameter, to inlet radius, to seat angle, to chamber shroud. This number is used to 'correct' the port velocity, given a cubic inch #, a cam profile, and a 'power band'. We know this works, we have tested it on 509", and 540" single carb motors. Also, in upper RPM (drag flatbottoms) unblown motors, we have found (aprox) 14.2 is the top for compression. We found 'too much drag' as a result of "squeezing" up all that compression. Just like a '2 stroke', the faster you turn it, the less compression you need. A 460" River Racer motor has run better (for us) at 9400RPMs, with 13.7.

[Infomaniac]

Very interesting stuff.
My question is: The program must have a "constant" for friction losses since it is using air volume variables.
Any idea what friction HP losses it assumes?

[Blown 472]

Can I play??
4.320 bore
3.750 stroke
7.70 c. ratio
14 psi boost at 6000 rpm
iron head port matched and bowl blended nothing else done to it. I dont know the volume.
stock head, with OE valve job and valves:
lift----in/ex
.100--60.8/51.1
.200-126.4/97.5
.300-186.7/132.7
.350-201.9/145.5
.400-208.3/150.3
.450-213.1/154.0
.500-217.9/156.4
.550-219.5/156.4
.600-219.5/156.4
.650-222.7/156.4
might be a little better with the bowl blend but I doubt it.:rolleyes:

[cstraub]

you'all may find this easier.
Take CFM of heads(max flow) x .2442 x No. of cylinders
Example
300 CFM x .2442 x 8 cylinder= 586HP @ 100%VE
I think .2442 is correct it might be .2552. I have not had enough coffee this morning. Anyway for those of you that know what your heads flow, this formula will give you what your engines potential is . . . a goal to shoot for.
Chris

[78Eliminator]

How bout my alcohol motor:
4.280 stroke
4.0 bore
12:5 comp (might be 13:1, have not cced heads)
Head information:
Brodix BB-2 Plus
312 cc Intake
119 cc Chamber Volume
2.250/1.880 Valves
Standard Exhaust Pattern and Valve Centerline
Cam is .700 lift, here is the head profile:
http://www.brodix.com/onlinecatalog/page1-2/BB-2-Pluschart.jpg

[UBFJ #454]

Chris -
I think if you'll check it out the constant you give as a multiplier is based on the assumption of only being able to achieve 100% VE and does not take into account special head work (Tricks, if you like) that can be done to achieve VE's of greater than 100%. Not saying anything bad about what you posted, only that it is just a First Approximation (in the case of our motor, .2552 yeilds a head flow that is just under 20% off which is quite a bit) and should be taken that way ... especially when you get into ProStock and ProMod Motors.
By the by, we have nothing but compliments for Stef's for the Special Dry Sump Pan and Oil Reservior System we had you'all fabricate for Ms. Moneypenny.

[UBFJ #454]

Since some knowledgeable people are responding to this thread, I thought I'd ask a Side Question .....
Does anyone know of a site which has information on, or, does anyone have an idea of how to compare #'s of blower boost to the "Boost" provided by a "Shot" of n2o ... Both increase the O in the cylinder so it seems to me there should be a simple way to compare them ... something like #'s Blower Boost per Volumetric Shot of n2o equivalency @ STP. Comments, Ideas ???

[cstraub]

Bear,
I e-mailed Fiat on some "known" VE numbers, but yes you are right, that formula is a baseline only to give you "potential" It is pretty normal for a comptetive engine to be in the 115% range.
Thanks for the compliment. We try to fabricate the best. I think our Offshore pan is the most impressive, hell when my little old 330HP BB pops, I am going to put one on it just because it looks cool.
I can calculate the boost aspect, I don't have a formula for NOS to compare. Boost is just converting it to Barometric pressure.
Chris

[Fiat48]

I see I am instantly behind in all the responses!:eek:
bigkatboat:
Numbers are numbers but experience is priceless! Actually lowering the compression ratio and the 2 stroke theory for a 9400 rpm motor is very interesting!
Infomaniac:
The friction losses defined as "Mechanical,Thermal, Pumping and intake cycle loses" default at 94.94%. Surely that's a variable but I left that alone while trying to match the engines in question. It is a factor I can adjust and here's an example of the changes it would make:
Taking Reher-Morrsions 565 as an example:
103.20 VE = 1020 Hp @ 7200 rpm and 106.40 torque efficiency making 820 ft lbs. Intake port area required 4.859. Mechanical loses 94.94%
Changing losses to 96%
Hp now 1047.127
Torque now same
Port area required = same
Blown 472:
Sorry. You're timing is off (inside joke).:D :D
I'm working on it.:D
78Eliminator:
Working on it.
cstraub69:
Sounds like the programs are near the same. My boost aspect also converts to barometric pressure. Don't have a way to do nitrous either. Excellent data on the Pro Stock stuff and Winston cup. :D

[Fiat48]

Originally posted by Blown 472
Can I play??
4.320 bore
3.750 stroke
7.70 c. ratio
14 psi boost at 6000 rpm
iron head port matched and bowl blended nothing else done to it. I dont know the volume.
stock head, with OE valve job and valves:
lift----in/ex
.100--60.8/51.1
.200-126.4/97.5
.300-186.7/132.7
.350-201.9/145.5
.400-208.3/150.3
.450-213.1/154.0
.500-217.9/156.4
.550-219.5/156.4
.600-219.5/156.4
.650-222.7/156.4
might be a little better with the bowl blend but I doubt it.:rolleyes:
For blowers the 29.92 barometric is converterted to PSI (Boost PSI X 2.035789617 + 29.92) Again..remember 29.92 not the real world unless you are sea level, 60 F and 0 humidity. Just a baseline. So barometer becomes 58.42 uncorrected.
100% VE and 100% TE
698.833 HP @ 6000 rpm Torque rpm 4000 with 644.314 lbs
Intake port area required (Choke area measurement) 3.054
and just for fun
120% VE and 120% TE:rolleyes:
838.6 Hp @ 6000 rpm Torque rpm 4000 with 773.17 ft lbs.
Intake port area required becomes 3.664.
If your rocker ratio is 1.5 (I think it is) I could do cam design. Wow..that head doesn't flow.

[Fiat48]

Originally posted by 78Eliminator
How bout my alcohol motor:
4.280 stroke
4.0 bore
12:5 comp (might be 13:1, have not cced heads)
Head information:
Brodix BB-2 Plus
312 cc Intake
119 cc Chamber Volume
2.250/1.880 Valves
Standard Exhaust Pattern and Valve Centerline
Cam is .700 lift, here is the head profile:
http://www.brodix.com/onlinecatalog/page1-2/BB-2-Pluschart.jpg
Controlled induction only cares about VE. Since I know this is a hydro motor, I'll do 7500 rpm for a base. Program only concerns itself with filling the cylinder.
29.92 barometer
100% VE and TE
760.4 HP @ 7500 rpm max torque at 5000 rpm 560.875 ft lbs.
3.996 Intake port area required (I believe you have that).
Have an intake flowed at 28" water at .500, .550, .600 lifts and I'll run the cam design for you.
Steal Blown 472's blower, bolt it on and alcohol in the tank:
Barometer becomes 58.42 (uncorrected) and:
1484.744 HP @ 7500 rpm max torque stays same as does port area required. And I guess we could add something to that Hp number for alcohol fuel.
:D

[cstraub]

Fiat no problem on the info. For some reason I get "alot" of scoop!!!! Blown, now remember, you go with one of our sealed divider pans and its worth at least another 30HP. . . .at least thats what some customers say!!!!!!!!!!
Chris

[78Eliminator]

I'm afraid. :o

[Fiat48]

Correction factors:
Example: 78Eliminator is in Chowchilla California on a "typical" race day. His altimeter reads 300 ft. It's 92 degrees temperature. Humidity is 25%.
He calculates the corrected altitude at 2813 ft. Air density is 84.75%
Barometer is corrected to 29.59
752 Hp at 7500 Torque falls to 554.688 lbs
He brings the boat to Reno, Nevada. Altimeter reads 4500 ft. It's 90 degrees. Humidity is 30%
Corrected altitude becomes 7899 ft. Air density 70.46%
Barometer is corrected to 25.33
643.762 Hp at 7500. Torque falls to 474.831 lbs.
78 leaves Reno, vowing never to return until he has a blower.
:D

[Fiat48]

Bore: 4.390
Stroke: 4.15
C/r 13.1
rpm = 7500
Cubic inches 502.5
Using closer to the real world 29.59 barometer
At 100% VE and TE
853.685 Hp at 7500 rpm Torque 629.668 at 5000 rpm. BUT 4.362 Intake port required.
If not enough Intake port area available then:
at 92% Ve and 100 TE
785.39 Hp and 629.668 torque
Intake port area required 4.013
Intake port area required definition= "This is the choke diameter area, and should be measured then corrected by average port flow air density. Using the valve-to-seat lap center diameter to calculate this area is acceptable in most cases".
That's as much defination as I have in the program. Will try to get more info.

[LakesOnly]

Originally posted by Fiat48
Bore: 4.390
Stroke: 4.15
C/r 13.1
rpm = 7500
Cubic inches 502.5
Using closer to the real world 29.59 barometer
At 100% VE and TE
853.685 Hp at 7500 rpm Torque 629.668 at 5000 rpm. BUT 4.362 Intake port required.
If not enough Intake port area available then:
at 92% Ve and 100 TE
785.39 Hp and 629.668 torque
Intake port area required 4.013
Intake port area required definition= "This is the choke diameter area, and should be measured then corrected by average port flow air density. Using the valve-to-seat lap center diameter to calculate this area is acceptable in most cases".
That's as much defination as I have in the program. Will try to get more info.
Thanks Fiat,
As you know, I was hoping I might be able to generate 800Hp with my engine displacement being reduced to just a 502. looks like everything will have to be theoretically perfect to pull it off.
I'm optomisitc.:D
Thanks again,
LO

[cstraub]

Fiat,
You have mail with the info you required. If you have any luck give me an update.
Chris

[Fiat48]

cstraub69: Thanks again.
Lakes: Port area available bugs me. Big motors use up cylinder head faster also. It'll be all about cylinder heads. But that's always the way.

[LakesOnly]

Originally posted by Fiat48
Lakes: Port area available bugs me.
I saw it; the runner volume that I gave you was as-cast/unported.
Indeed, it'll be close.
LO

[cstraub]

Lakes,
You will be able to crutch it with cam. I cammed a 496 CID BBC about 3 years ago. Had a set of untouched pro1's on it. 2 x 4 motor and we had a target of 900HP. Motor was 15.2 to 1. we were going to have to spin her to make power, we ran out of cross section so the cam profile went nutz!!! After it was all said and done, on Al Parkers dyno it made 918HP. Parker didn't think it was possible. .. my customer was happy.
Chris

[LakesOnly]

Originally posted by cstraub69
Lakes,
You will be able to crutch it with cam. I cammed a 496 CID BBC about 3 years ago....Motor was 15.2 to 1. we were going to have to spin her to make power, we ran out of cross section so the cam profile went nutz!!! After it was all said and done, on Al Parkers dyno it made 918HP. Parker didn't think it was possible. .. my customer was happy.
Chris
Thanks Straub,
I considered upping compression too (in search of more hi-rpm HP), but that would effectively call out for lots of help in both areas you and Fiat have noted (both cam and intake port cross-section). While I haven't ruled these variables out, I feel that that amount of HP still remains a tall order in my world (with what components I am working with, anyway). So I'm taking my time on this build...gathering lots of data.
LO

[cstraub]

Well hell I forgot about my Ford truck pull engines. . .this will make you feel better. OEM DOVE heads with the exhaust flange plates,porting, and angle milling. 13.5 to 1 with flat tops. Destroked to 3.750" and using a 2.100" crank pin diameter. Dual plane intake and a solid flat tappet custom cam, she makes 718HP at 7800RPM. When my customers customer pulls it, he usually puts about 10 ft on the closesest BBC. Cam is radical for a flat tappet but would be considered an average roller.
I would put the compression to her...
Chris

[Fiat48]

You've done it now! Telling Lakes you know a Ford that puts 10 ft on a BBC. :eek!
Hold on to your Hats!!:D

[Blown 472]

Originally posted by Fiat48
For blowers the 29.92 barometric is converterted to PSI (Boost PSI X 2.035789617 + 29.92) Again..remember 29.92 not the real world unless you are sea level, 60 F and 0 humidity. Just a baseline. So barometer becomes 58.42 uncorrected.
100% VE and 100% TE
698.833 HP @ 6000 rpm Torque rpm 4000 with 644.314 lbs
Intake port area required (Choke area measurement) 3.054
and just for fun
120% VE and 120% TE:rolleyes:
838.6 Hp @ 6000 rpm Torque rpm 4000 with 773.17 ft lbs.
Intake port area required becomes 3.664.
If your rocker ratio is 1.5 (I think it is) I could do cam design. Wow..that head doesn't flow.
My heads might be a little better but they have the stock valves, and all I did was use the mopar porting templates and a port match on the intakes.
I think I saw lakes running towards the bench racers area.:D :D

[LakesOnly]

Originally posted by cstraub69
...OEM DOVE heads with the exhaust flange plates,porting, and angle milling. 13.5 to 1 with flat tops. Destroked to 3.750" and using a 2.100" crank pin diameter. Dual plane intake and a solid flat tappet custom cam, she makes 718HP at 7800RPM. When my customers customer pulls it, he usually puts about 10 ft on the closesest BBC. Cam is radical for a flat tappet but would be considered an average roller.
I would put the compression to her...
Chris
Well, I'll be damned; D0VE heads with stock intake port-size supporting 7800 rpm N/A? I thought intake flow would have stalled/slammed the backside of the port long ago...I guess with enough engine vacuum (by way of rpm & c/r), all hope is not lost.:)
My SCJ heads--with the right tweak, more c/r and cam--may offer up what I am shooting for afterall...
Fiat, I remember what you told me about your first cam grind with this little program...the "exchange" with Erson; the results at Sacramento...maybe we can toy with profiles one day if I pass thru town?
LO

[Fiat48]

Lakes, That would be fine. But if it were me I do believe I would work with cstraub69 if he will do a camshaft for you. From all indications he has the same program which I have plus another program that's more advanced. And he has someone willing to grind the cams. Plus experience and having Ford's out there doing it.
You'll have to have flow numbers on the heads for sure.
Sounds like a commercial.
:D

[LakesOnly]

Okay man, let's try to steer this thread topic back onto course...
Turns out the intake port cross-section of an unported SCJ head is 4.19 square inches as-cast, and mine will be at least gasket matched to FelPro 1231 SCJ intake gasket port cutout--which is 4.6 inches--and port matched down the runner up to the 2.25 intake valve.
This is now comparable to the (program deemed) necessary 4.362" that raised eyebrows earlier on this page.
So...:
4.39"B
4.15"S
4.4 Choke
13.5:1 c/r (up a bit...)
7500 rpm (how about one at 8000 too?)
Ported Int/Exh
.1 81/57
.2 156/112
.3 227/151
.4 278/175
.5 311/192
.6 343/204
.7 353/207
.8 375/211
Everyone please spare me the ridicule of the poor exhaust flow numbers; fact is D0VE exhaust flow better than OEM SCJ's...I'm working on that too.:devil:
LO

[Fiat48]

I need to find the book to be sure that intake port choke area is being figured correctly. Seems there was something about that I need to check.
But I can't seem to locate it. Chris has given me a phone number and I hope to locate the author for another manual. But so as to not keep you in suspense, I will do it anyway.
I'm not sure you have the "area" in question, but if you do then:
Bore 4.390
Stroke 4.15
c/r 13.5
assuming you have 4.4 available
100% VE and TE
Keeping the barometer at 29.59
886.5 Hp @7500 653.8 ft lbs torque at 5000 4.362 required.
or
945.6 Hp at 8000 same torque But "Intake Port area required" goes to 4.653
Screen shots of entire program. With specs you gave me after above posting. Screens 1 thru 4 are work screens.
No warranty expressed or implied.
http://www.***boat.com/image_center/data/503/374CILakes1-med.JPG
http://www.***boat.com/image_center/data/503/374CILakes2-med.JPG
http://www.***boat.com/image_center/data/503/374CILakes3-med.JPG
http://www.***boat.com/image_center/data/503/374CILakes4-med.JPG
http://www.***boat.com/image_center/data/503/374CIlakesr1-med.JPG
http://www.***boat.com/image_center/data/503/374CILakesr2-med.JPG
109 + 115 / 2 = 112 LS.
I found the "Cam Plots" to be most important, not just at .050 specs.

[Kindsvater Flat]

curiousity has got me now
Current 440 N/A
bore: 4.320 +.030
stroke: 3.76
compression: 13:1
600cfm x 2
Rpm: 6500
New 440 8-71 w/ 8lbs ( yes its a pussy boost)
bore: 4.320 +..060
stroke: 3.76
compression: 8:1
Rpm: 6500
830cfm x 2
Both motors use the stage VI alum heads

[Fiat48]

Originally posted by Kindsvater Flat
curiousity has got me now
Current 440 N/A
bore: 4.320 +.030
stroke: 3.76
compression: 13:1
600cfm x 2
Rpm: 6500
New 440 8-71 w/ 8lbs ( yes its a pussy boost)
bore: 4.320 +..060
stroke: 3.76
compression: 8:1
Rpm: 6500
830cfm x 2
Both motors use the stage VI alum heads
Unblown using 29.59 barometer
100% Ve & TE
658.2 Hp at 6500 Torque is 560.146 at 4333 rpm
Intake port area required 3.363
Blown with 8 lbs boost = barometer to 45.88
1.2 miilion HP @ 6500 when run at CFW J/K
:D
100% VE & TE
636.699 Hp @ 6500 Torque is 541.8 lbs at 4333 rpm.
Intake port area required grows to 3.410
:confused: ;) You lost on the beans what you made on the potatoes.
Let's do 15 lbs boost
Barometer moved to 60
832 .6 HP at 6500 Torque is 708.637 at 4333
Intake port required 3.410
Think about that. You increase cubic inches but lose the compression. Cubic inch goes up and so does the air demand to feed it. You put a blower on at 8 lbs of boost and find yourself with less power than you had with a smaller motor with 13.5 to 1 compression. Especially since you lose the power to drive the blower.
:eek:

[Kindsvater Flat]

Boy that sucks Bob. Now what if I switched pulleys. 63 top 61 bottom for 8lbs. What would the boost be if I flipped them?
Originally posted by Fiat48
Unblown using 29.59 barometer
100% Ve & TE
658.2 Hp at 6500 Torque is 560.146 at 4333 rpm
Intake port area required 3.363
Blown with 8 lbs boost = barometer to 45.88
1.2 miilion HP @ 6500 when run at CFW J/K
:D
100% VE & TE
636.699 Hp @ 6500 Torque is 541.8 lbs at 4333 rpm.
Intake port area required grows to 3.410
:confused: ;) You lost on the beans what you made on the potatoes.
Let's do 15 lbs boost
Barometer moved to 60
832 .6 HP at 6500 Torque is 708.637 at 4333
Intake port required 3.410
Think about that. You increase cubic inches but lose the compression. Cubic inch goes up and so does the air demand to feed it. You put a blower on at 8 lbs of boost and find yourself with less power than you had with a smaller motor with 13.5 to 1 compression. Especially since you lose the power to drive the blower.
:eek:

[Fiat48]

Assuming you are 8mm drive. 1 tooth difference is 2%. So you'd be going from 2 under to 2 over. Not sure of boost you'll get. Depends on a lot of things. Maybe there's a chart to give you an idea. But it'll help.
Probably wind up with the thing 10 over for some power. That would be 5 teeth difference between pulleys.

[Kindsvater Flat]

Ok so there is a 20hp difference, but won't there be a drivability difference between the 2 motors? Or is it still 600hp (just a figure) no matter what.

[Fiat48]

In my opinion, we lost torque. Plus driving the blower there would be a physical pumping loss. Down on power everywhere.
Torque x rpm = HP.
1st time I ever ran across this. We gave up 5 points of compression. That's a lot.
Changing the compression ratio to 9 to 1
716.2 Hp at 6500 and 609.6 lbs of torque at 4333 rpm
3.410 port area required.
771 Hp if you twist the 9 to 1 to 7000
3.672 port area required.
Food for thought.

[Kindsvater Flat]

Well this sucks.

[INEEDAV]

That is kinda f'ed up sounding.
I thought I was learning something here till this happened.:confused:
Bob do we know enough about the engine that is going in my boat to calculate this?

[Kindsvater Flat]

Well the compression is 8.2:1 with the close chamber heads. Being that they are ported and not stock nor stock valve size I'm sure this plays a factor in it. Either way at least it will look cool with the blower on it. Why else would I ask for the full polish :D
Originally posted by Fiat48
In my opinion, we lost torque. Plus driving the blower there would be a physical pumping loss. Down on power everywhere.
Torque x rpm = HP.
1st time I ever ran across this. We gave up 5 points of compression. That's a lot.
Changing the compression ratio to 9 to 1
716.2 Hp at 6500 and 609.6 lbs of torque at 4333 rpm
3.410 port area required.
771 Hp if you twist the 9 to 1 to 7000
3.672 port area required.
Food for thought.

[Fiat48]

Originally posted by INEEDAV
That is kinda f'ed up sounding.
I thought I was learning something here till this happened.:confused:
Bob do we know enough about the engine that is going in my boat to calculate this?
LOL..Yeah...real mind blower. I keep running the numbers and that's what she says.
Remember we rated both at 100% VE. That doesn't mean he has 100% Ve now. Compares 2 engines both designed for 100% VE. It only knows numbers.
Billy..you are about the same dealio as 78Eliminator's. Only 8 CI difference.

[Fiat48]

Originally posted by Kindsvater Flat
Well the compression is 8.2:1 with the close chamber heads. Being that they are ported and not stock nor stock valve size I'm sure this plays a factor in it. Either way at least it will look cool with the blower on it. Why else would I ask for the full polish :D
Not really. CI is already assuming you have what's required to fill the cylinder and therefore can make 100% (or more) VE.
No head flow numbers go here. Just Bore, stroke, compression ratio and available air to fill that cylinder. Cylinder head flow numbers are used with the camshaft design end and a weak flowing head will require more cam duration. Take a look at Lakes screen shots for the whole program.
Your deal: Twist it higher, raise the compression, raise the blower boost.

[Kindsvater Flat]

Originally posted by Fiat48
Your deal: Twist it higher, raise the compression, raise the blower boost.
But its a mopar. :(
at least I'm honest:D

[INEEDAV]

Bob I guess what you are saying is don't run my boat here close to the house at Eleven Mile Resevoir, it elevation is about 9000ft.
Mike, one word. ALCOHOL:D

[Blown 472]

Originally posted by Kindsvater Flat
But its a mopar. :(
at least I'm honest:D
Shit, dont be afraid to lean on the mopar my mule has been pulling strong for 5 years and has seen 7k many a time.

[Fiat48]

Mike. Read this chart. You'll see why we are seeing what we are seeing. http://www.goodvibesracing.com/Compression%20Ratio.htm

[INEEDAV]

Looking at that chart, his engine is getting back not quite to the fcr that is was originally(unblown) correct? And the horsepower number doesn't take into effect the parasitic loss of the blower itself.

[h2ojet001]

I came in on this thread a little late, but I am a little confused as to what is meant by intake port area or choke area. How is this measured. Doesn't the amount of air trapped in the cylinder have to do with the point at which the intake valve closes which is an important parameter in order determine what compression is needed to operate efficiently with a particular cam. I am trying to select a cam using some of this info but so far but haven't been able find something that makes sense. Let me know if any of this makes sense.
Barry

[RiverCityJet]

Fiat, you're kinda scare'n me now after seeing K-flats numbers
so can ya give me a Shot?.
454 + .030
4.250 stroke
8.7 cr
Large ovelport heads/ported 2.19/1.88's
8-71 7psi / intercooler
830 cfm's x2
RPM's ? ( it's for a jet )
RCJ

[cstraub]

Fiat I feel for you. . . .
Chris
.

[flat broke]

When you say 454 +.030, does that mean that you have a 454 block that is .030 over, because that would be a 4.280 bore which when combined with your 4.250 stroke would be like 4.89 CI. Otherwise, you'd have a 4.280 bore and a 4.00 stroke if it was just a bored out 454.
Chris
Originally posted by RiverCityJet
Fiat, you're kinda scare'n me now after seeing K-flats numbers
so can ya give me a Shot?.
454 + .030
4.250 stroke
8.7 cr
Large ovelport heads/ported 2.19/1.88's
8-71 7psi / intercooler
830 cfm's x2
RPM's ? ( it's for a jet )
RCJ

[Fiat48]

INEEDAV:
Yeah that's the way I see it. Looks like it would take near 9 lbs of boost just to get him back even with his unblown motor. But 5 points of compression is a bunch to give up. But really with 13.1 compression on the unblown deal he shouldn't be pump gas anyway. So all he has to do is just run more boost in the blown motor and he'll make more power. Remember this is all about power you COULD make if 100% VE attained. Maybe his unblown deal 90% now.
h2ojet001
I sent you a PM.
RiverCityJet:
Remember (read the first post carefully) that this is power available IF YOU ACHIEVE 100% VE. Ve is all about filling the cylinder. Cylinder head flow and camshaft and other factors may limit you in filling that cylinder and your actual VE might be 90%. These numbers I give are what CAN BE ACHIEVED with 100% VE. Naturally you would design an engine to be 100% or more efficient.
I get the feeling some have seen the K flat deal and are going "Oh my God, he's gonna go slower with a blower!" Go back and read what happening between the two motors and you'll get some understanding. That said:
On a typical day at low elevation and 7 lbs of boost, at 6000 rpm's:
657.8 Hp and 606 ft lbs torque. If your engine had 100% VE
But if only 90% VE efficent due to cylinder head design/flow or camshaft design then at 6000 RPM's:
592 Hp and 545 Ft lbs of torque. Only 90% VE.
cstraub69:
Lol. Yeah.

[RiverCityJet]

flate broke, Thanks for pointing that out but, I have a pretty good feeling that Fiat 48 knows what the standered bore and stroke of a 454 is. I didn't feel the need to have to tell him what my motor would equate too. Now to answer your question, yes it is a 489ci, if it were only bored .030 over and not stroked, it would be a 460ci.
RCJ

[RiverCityJet]

Oh, by the way, thanks! Fiat 48
RCJ

[Fiat48]

Originally posted by RiverCityJet
flate broke, Thanks for pointing that out but, I have a pretty good feeling that Fiat 48 knows what the standered bore and stroke of a 454 is. I didn't feel the need to have to tell him what my motor would equate too. Now to answer your question, yes it is a 489ci, if it were only bored .030 over and not stroked, it would be a 460ci.
RCJ
I figured it the way you said 489.

[sam t]

fiat, how about mine: 4.535bore, 4.5 stroke 8-71/intercooled 8psi of boost, 8.8 static compression, dart pro 1 345cc fully ported heads, .730 lift cam. thanks sam

[sam t]

sorry fiat, 2 -1150's and 2.325 x 1.925 valves thanx

[565edge]

I got two combos.
motor#1 -4.25 stroke,.400 long rod,4.600 bore.Dart cnc 355 heads,1 1150 dominator. 700 lift solid roller.10.5 compression.
Motor 2- 4.25 stroke,.400 long rod,4.625 bore,dart cnc 355 heads,2- 1150 dominators,.700 lift roller cam,8.5 to 1 comp,14-71 blower,10 pounds boost.
Motor #3--same stroke,4.600 bore,15-1 comp,.800 lift solid roller.Tunnel ram with two 1150 dominators.same dart cnc 355's.Valves on all three are 2.300 and 1.880.

[Kindsvater Flat]

Fiat:
Called Tim at SuperCharger USA and he said if I flipped the pulleys I would go from 8lbs to 12lbs. He said that would be the max without oringing the block. He said 1 to1 ratio would 10lbs.
I talked to another guy and he said the blower should produce more hp since the VE would be more efficient than the N/A deal.
Also I think you're right and I will be sending $25 for you going through the trouble of processing this information. Thanks.

[Fiat48]

sam t:
I need RPM.
565edge:
I need RPM
Remember guys, Controlled induction's Hp and torque assumes you have the head, camshaft and induction system to get the VE (fill the cylinder). Only as strong as your weakest link. So I only need Bore, stroke, compression ratio, boost and top rpm you see.
Kindsvater: I gave that consideration to better breathing also. But I don't know. You could be the first to try it.
But common sense tells me that the power loss of driving the blower and we assumed both motors were designed for 100% VE, that I would have to agree with the program that there would be less power with the blown motor than the naturally aspirated motor.

[565edge]

Originally posted by 565edge
I got two combos.
motor#1 -4.25 stroke,.400 long rod,4.600 bore.Dart cnc 355 heads,1 1150 dominator. 700 lift solid roller.10.5 compression.
Motor 2- 4.25 stroke,.400 long rod,4.625 bore,dart cnc 355 heads,2- 1150 dominators,.700 lift roller cam,8.5 to 1 comp,14-71 blower,10 pounds boost.
Motor #3--same stroke,4.600 bore,15-1 comp,.800 lift solid roller.Tunnel ram with two 1150 dominators.same dart cnc 355's.Valves on all three are 2.300 and 1.880.
Motor #1 6,000 rpm.Motor#2-6500 rpm.motor#3 7300 rpm.
Samt's motor spins 6300rpm.Can you show it at 6300,6600,and 7000rpm.Thanks abunch.

[Fiat48]

565 edge:
Motor #1 6000 rpm
4.600
4.250
10.5
unblown
29.59 barometer
100% VE and TE
620 .2 Hp @ 6000 571.8 ft lbs torque at 4000 rpm
Motor #2 6500 rpm
4.625
4.250
8.5
10 lbs boost
Barometer 49.95
100% VE and TE
928 Hp @ 6500 rpm 789 ft lbs at 4333 rpm
Motor #3 7300 rpm
4.600
4.250
15
unblown
Barometer 29.59
1078 Hp at 7300 rpm 816.9 Ft lbs at 4866 rpm
Intake port area required is 4.774. Better be as good a heads as Reher-Morrison's deals or better. It'll be all about head for this motor.
Repeat after me: This is only the capabilitys of my Bore/stroke/ cr/ rpm/ boost. I could be making less power than that. This is the "Blue Sky" so to speak.

[Fiat48]

Sam T:
6300 Rpm
4.535
4.5
8.8
8 lbs boost
Barometer 45.87
100% VE and TE
870.7 Hp @ 6300 rpm 764.5 Ft lbs at 4200 rpm
Boost may go up with rpm but anyway:
at 6600
912.2 Hp at 6600 rpm 764 ft lbs at 4400 rpm
at 7000
967.49 Hp at 7000 rpm 764 ft lbs 4666 rpm
Better be good ass heads on these big animals to get close to these numbers. Big motor use heads up quick.
Repeat after me: This is only the capabilitys of my Bore/stroke/ cr/ rpm/ boost. I could be making less power than that. This is the "Blue Sky" so to speak.

[565edge]

Man your right on the money.Thank you.My motor combo now is the #3 motor.Im going to re-build this motor either blown or n/a pump gas deal for a bigger boat.I thought the blown motor might make more power.It will be innercooled.Thanks again.Very impressive on your part.Did you right this program.

[565edge]

Originally posted by Fiat48
Sam T:
6300 Rpm
4.535
4.5
8.8
8 lbs boost
Barometer 45.87
100% VE and TE
870.7 Hp @ 6300 rpm 764.5 Ft lbs at 4200 rpm
Boost may go up with rpm but anyway:
at 6600
912.2 Hp at 6600 rpm 764 ft lbs at 4400 rpm
at 7000
967.49 Hp at 7000 rpm 764 ft lbs 4666 rpm
Better be good ass heads on these big animals to get close to these numbers. Big motor use heads up quick.
Repeat after me: This is only the capabilitys of my Bore/stroke/ cr/ rpm/ boost. I could be making less power than that. This is the "Blue Sky" so to speak.
I used jer's jet boat calculator and its pretty close.It says at 6300rpm going 102mph 866hp.Thats in a 21' daytona jet.

[Fiat48]

Originally posted by 565edge
Man your right on the money.Thank you.My motor combo now is the #3 motor.Im going to re-build this motor either blown or n/a pump gas deal for a bigger boat.I thought the blown motor might make more power.It will be innercooled.Thanks again.Very impressive on your part.Did you right this program.
No, I am just a stupid racer. I helped prove the program worked when it was first put together. I am told the program is no longer available.

[bigkatboat]

In an engine turning 3000 RPMs, the 'intake charge' goes into the cylinder at 100 MPH (example). It fills the cylinder at 100% VE. The same motor at 8000RPMs, has an intake flow speed of 400MPH. The flow speed has changed because of the head port work, and the cam timing, along with the compression ratio, and the useable RPM range. IF, a high speed flow is captured (valve events) by the cylinder at the correct time, it COULD produce a VE greater than 100%. VE is rated on the volume of the cylinder with a MIXTURE of AIR and fuel. Velocity, when slowed or stopped may cause compression, and so to (in this case) the VE is raised because the "high speed charge" is suddenly captured in the cylinder. It may be entering the cylinder at a (positive) boost state, and this would most certainly cause a VE over 100%. Think of this as an air nozzle blown across a 'pinwheel', it is not quite the same but the outcome is a greater (compression) pressure on one side of the pinwheel blades than the other. If your intake, cylinder head, and exhaust, create the "air flow effect" the 'charge' will grow with RPMs. In the 1950's Isky called it the "5 cycle cam". I don't think I'm crazy, but it has worked for me this far! This example is UNBLOWN, but it is very close for blown motors too. (cam change)

[058]

Fiat, Can you expand on the head flow differences needed between gasoline and alcohol since alcohol takes up more volume than gas? In the early days this didn't seem to be as much of an issue but since engines are getting bigger than most heads can handle so the question would be is an alcohol engine "tapped out" before a gasoline engine of the same displacement and same head and what would be the difference in port/valve bowl be needed in each head to address the difference in wet flow of the two.

[Dave C]

Fiat,
Please,
4.5 x 4.5
9.5
5,800 (max)
I am assuming 95% (100% for kicks) V/E but I am probably wrong cuz I don't have a clue.
Any idea how to calculate intake port area/choke area for Dart Pro 1's 345's with 2.3's?
Thanks
Dave

[cstraub]

058,
I'll take that one. . .Fiat and I touched on that in PM"s yesterday. Since alky is an O bearing fuel it has an advantage over gas. Since I cam alot of dirt late models, sprints, and drag alky engines I have had the chance to experiment in this. Using a program to figure air speed in a given intake runner volume for a given Max rpm range, I can come up with a percentage of increase to add to the intakes flow rate. Buy doing this the camshaft is calculated specifically for the alky engine. This inturn makes the neccessary intake lobe smaller due to the fact the air is "inhanced" with the oxygen.
Chris

[Blown 472]

Originally posted by cstraub69
058,
I'll take that one. . .Fiat and I touched on that in PM"s yesterday. Since alky is an O bearing fuel it has an advantage over gas. Since I cam alot of dirt late models, sprints, and drag alky engines I have had the chance to experiment in this. Using a program to figure air speed in a given intake runner volume for a given Max rpm range, I can come up with a percentage of increase to add to the intakes flow rate. Buy doing this the camshaft is calculated specifically for the alky engine. This inturn makes the neccessary intake lobe smaller due to the fact the air is "inhanced" with the oxygen.
Chris
0 bearing fuel? please explain.

[cstraub]

Oxygen, Blown!!!!! Hey per PM, Fiat is out for awhile. . .and NO I am not subing for him!!!!!!!
Chris

[Blown 472]

Originally posted by cstraub69
Oxygen, Blown!!!!! Hey per PM, Fiat is out for awhile. . .and NO I am not subing for him!!!!!!!
Chris
Holy hangover batman, sheesh. Thanks, kinda like that 49.5% oxygen laden nitro stuff?

[058]

Chris, thanks for taking the time to answer.

[cstraub]

No problem, I just had an irrate customer on the phone, his pan of 6 weeks building arrived by the "carrier" in pieces!!!!!
Chris

[Fiat48]

Originally posted by Dave C
Fiat,
Please,
4.5 x 4.5
9.5
5,800 (max)
I am assuming 95% (100% for kicks) V/E but I am probably wrong cuz I don't have a clue.
Any idea how to calculate intake port area/choke area for Dart Pro 1's 345's with 2.3's?
Thanks
Dave
Unblown with 29.59 barometer
5800 rpm
95% Ve and TE
522.5 Hp at 5800 rpm Torque 498 lbs at 3866.6 rpm
3.651 intake port area required.
100% VE and TE
549.6 Hp at 5800 Torque 524.267 Lbs at 3866 rpm
3.844 Intake port area required.
I am sure you have at least the port area for 100% (at that rpm).
This porgram was "dug out of mothballs" as it's been years since I used it. I need to figure out how to calculate that Intake Port area required the way for sure that the program wants it calculated. Haven't had a chance to do that but I will.
But the heads you have now are at least as good (and possibly superior to what I had figured as 4.051 which was a set of Dart 360's (one of the first sets as a matter of fact) that were ported by Engine Prototype Development in the 80's. Yes, I am old. :(

[cstraub]

Fiat,
Glad you are back. EPD, haven't heard that name in awhile. If you want to shoot the breeze next week, you can call me at 423 854 0007. . .UPS just showed up so my oil changer for the boat is here and I am working on it.....
Chris

[Fiat48]

Yes, Alcohol oxygen bearing fuel. How much has always been a debate. But no way as much as nitro.
Chris designing camshafts to further comment that fuel and has the "feedback" from the racers it's working.
Many thanks to Chris who has worked with these cam design programs and gets inside information.
Bigkatboat with his hands on experience and what works for him makes this thread an education for all. Many thanks.
Edit: Chris, I am booked and typing while eating. Get with you another time.

[Dave C]

thanks

[Fiat48]

Here is what I found on "Intake Port Area Required"
If you are following this dealio...then please reference the screen shots for the cam deal I did for LakesOnly earlier in this thread.
Screen # 1 : I input barometer, bore, stroke, cylinders, compression ratio, rpm, desired Ve and desired Te, and Inertia ram. Intake port area required is automatically calculated as to what would be required to reach the VE and TE.
If I do not have that area then I can go to work screen 4 and enter the area I have. The program will adjust accordingly to the VE and TE I would have available with my measured port area. (actually it will do many other things..but we'll leave that for now.)
There is a built in help screen.
Intake Port Area Required is Defined in the help program as:
"
This is value for the choke diameter area, calculated to the average port air density, required to achieve 300 FPS Average Port Velocity <or value entered if altered>. This value can be used to determine the valve-to-seat lap area."
On screen # 4 where you can enter your own measured amount (in square inches) of what you have in "Intake port area AVAILABLE".
Help screen on that page reads " This is the choke diameter area, and should be measured then corrected by the average port flow air density. Using the valve-to-seat lap center diameter to calculate this area is acceptable in most cases."
So you can measure the "valve to seat lap center" and convert that to square inches and use that as the available area. Or you can measure your port at it's most restrictive part (choke) area and convert that to square inches and use that figure. I'd have to say that measuring the ports smallest are would have to be the most accurate. Just measuring the seat lap center could be misleading as not the most restrictive area.
If you measure your lap area or most RESTRICTIVE (smallest) part of the port then you can go here and figure square inches:
http://www.newcovenant.com/speedcrafter/calculators/runnerarea.htm
If you figure I am wrong...let me hear about it.